I transferred money all the time to my bank in Canada. It is a bit complicated, but once you figure out the process it is relatively easy. The first time, you need to take someone from the school office or a student with you to do the translating. The forms are in English though.
You need to make sure that the school gives you a copy of the tax receipt from the govt to show you paid taxes on your income. This was newly introduced about 3 yrs ago and was a total pain in the butt because the university staff couldn't/wouldn't figure it out. Once they figured it out, it was a piece of cake getting the correct paperwork.
Also, many many Foreign Teachers take a Chinese friend or student with them and have them do the transfer for you. They don't need to show any proof of income, just the ID card.
You will need to get all the codes from your bank to do a direct transfer. Swift Code, Bank Code, etc etc. Your bank will know what you need to do the transfer.
I never used Western Union but many others did/do. It is easier for Americans to use as Western Union will only accept US funds (not Canadian funds). Not sure about British funds. I would have had to change my RMB into US dollars, then whoever picked up the money would have had to deposit it into my bank and I would have had to pay the exchange rate to go from US to Canadian.
Anyhow, whatever way you choose, the process will prevent the need for you to stuff your suitcase full of RMB.